Tensionless bulking apparatus and method



July 29, 1969 J. c. QATFIELD ET 3,457,602

TENSIONLESS BULKING APPARATUS AND METHOD Filed Nov. 14, 1967 2Sheets-Sheet 1 INVENTORS JOHN C. OATFIELD SAMUEL J. DAVIS JOHN W. COUICKATTORNEY y 1969 J. c. OATFIELD ET AL 3,457,602

TENSIONLESS HULKlNG APPARATUS AN!) METHOD Filed NOV. I4, 1967 2Sheets-Sheet D //Y Ma ,5 OIVC N T m m m WOJ.C "H N L .ICMW A HMH UnitedStates Patent 3,457,602 TENSIONLESS BULKIN G APPARATUS AND METHOD JohnC. Oatfield, Cary, and Samuel J. Davis, Chapel Hill, N.C., and John W.Couick, Etowah, Tenn., assignors to Monsanto Company, St. Louis, Mo., acorporation of Delaware Filed Nov. 14, 1967, Ser. No. 682,804

Int. (:1. D02g 3/00 U.S. c1. 2s 1.2 11 Claims ABSTRACT OF THE DISCLOSUREBACKGROUND OF THE INVENTION Field of the invention This inventionrelates to the development of all of the available bulk and shrinkage intextured yarns and, more specifically, to the method and apparatus forraising the temperature of the textured yarn sufiiciently to allow allof the available bulk to be developed while maintaining the yarn in atensionless and frictionless state.

Description of prior art The yarns including but not limited to,acrylonitrile polymer filament yarns may be textured in a variety ofways. One method for texturing acrylic yarns for example is disclosed inUS. Patent No. 3,022,565 to Fitzgerald wherein the yarn was drawn from asupply source, stretched while heated to a temperature above the secondorder transition temperature [normally for polyacrylonitrile yarns 160F. to 170 F. in wet heat and 195 F. to 215 F. in dry heat] to produce aconventionally unstable yarn and concurrently therewith to insert twistin the yarn, cooling the yarn to set the twist, untwisting the yarn andtaking the yarn up by a suitable means. Fitzgerald developed the crimpor bulk by heating the yarn above the second order transitiontemperature while the yarn rested in a relaxed state.

The prior art methods of relaxing and bulking textured yarn include thefollowing: treating the yarn while in the skein form at 185 F. for fiveminutes in a steam atmosphere; utilizing radiant heat lamps to relax theyarn under dry heat conditions after the yarn has been piddled onto acontinuous conveyor belt followed by immediate takeup under controlledtension; and fabricating the textured yarn into piece goods such ascarpets and treating the goods in accordance with one of the abovemethods or developing the bulk by the dying of the piece goods.

Bulking processes of this type rarely develop more than 50% of theavailable bulk due to the tension forces and frictional forces exertedon the yarn while at a temperature of above the range of 185-225 F. Eventhe yarns own weight is enough to prevent the full development of theavailable bulk.

Another bull-ting means employed in the past is that of bulking atextured yarn while the yarn is traveling in the vertical path, eitherupwardly or downwardly; however, such a method develops only about 60%of the available bulk for as mentioned above, the weight of the yarnalone is sufiicient to prevent bulk development to 3,457,602 PatentedJuly 29, 1969 ice the degree that is inherent in the yarn. Therefore, itcan be seen that a method for developing all of the available bulk in atextured yarn would be a tremendous advancement over the prior art.

SUMMARY OF THE INVENTION In accordance with this invention, a method andapparatus is provided which is capable of developing all of theavailable bulk in certain textured yarns. The essential parts of theapparatus include a substantially enclosed chamber, a feeding device forpulling the textured yarn from a source and directing it into thechamber, an open meshed conveyor belt which partially resides in thechamber and which extends outwardly through a selected wall thereof,heating elements positioned in the chamber beneath the conveyor belt,fans mounted for rotation in the chamber for directing air into contactwith the heating coils and upwardly through the conveyor belt and takeupmeans for further cooling the bulked yarn after it has passed out of thechamber and means for packaging the yarn.

The method according to this invention includes the steps of directingtextured yarn into a heated chamber at a predetermined rate, receivingthe yarn in the chamber by an open meshed conveyor belt which moveslaterally at a speed being less than the speed of the incoming texturedyarn, raising the temperature of the textured yarn to above the range of-225F. while simultaneously supporting the yarn above, the surface ofthe conveyor belt in a substantially tensionless and frictionless stateby upwardly moving air to develop all of the available bulk, moving thebulk yarn out of the chamber without subjecting the yarn to externalforces and lowering the temperature of the yarn below 185 F. beforesubjecting the yarn to any frictional or tension forces. After the yarnhas been cooled to a temperature of below 185 F., it is then furthercooled and taken up in the usual manner.

Therefore, an object of this invention is to provide a method fordeveloping substantially all of the available bulk in textured yarns.

Another object of this invention is to provide a bulked yarn that iscapable of being packaged into a hard package which will retain its fullbulk after packaging.

A further object of this invention is to provide a means for fullydeveloping the bulk in synthetic textured textile yarns while the yarnis in a completely tensionless and frictionless state.

Still another object of this invention is to provide a means for settingthe fully developed bulk in the yarn so that the yarn retains all of thebulk developed during the bulking process.

DESCRIPTION OF THE DRAWINGS FIGURE 1 is a prospective view of theapparatus of this invention having portions of the apparatus cut away toshow selected interior components; and

FIGURE 2 is an elevation, section view taken along lines 2-2 of FIGURE 1illustrating the path of the yarn through the apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A base plate or floor10 is provided to support and locate the elements of apparatus. Baseplate 10 supports an insulated chamber 11 which defines a cavity 1 andincludes top wall 13, end Wall 14 and side walls 17 and 18. Top wall 13is provided with an opening 15 which is adapted to receive cover 16 forproviding easy access to cavity 12. A thermocouple 20 is mounted on andextends through cover 16 and is adapted to monitor and record the yarntreatment temperature within chamber 11. The temperature control andrecording means which are of the conventional type are not shown.

Textured yarn 24 is pulled from a source [not shown] by means of feedrollers 25 and 26 and is directed into cavity 12 through slot 27 in topwall 13. Any number of strands of yarn may be processed by the apparatusof this invention simultaneously. Feed rollers 25 and 26 are journaledin a pair of spaced-apart plates 28 and 29 [plate 29 not shown] whichare secured to and extend upwardly from top wall 13. Feed roller 25 ispositively driven by motor 30 and feed roller 26 is tangential andfrictional contact with roller 25 and is driven thereby.

Open meshed conveyor belt 32 has its major portion residing in cavity 12and moves in a path beneath slot 27 outwardly from cavity 12 throughslot 33 in end wall 14 and returns to cavity 12 through slot 34 in endwall 14 to its point of beginning. Conveyor belt 32 is received by andis suspended between conveyor drums 35 and 36. Conveyor drum 35 issecurely mounted onto shaft 37 which is appropriately journaled in sidewalls 17 and 18 and which extends through side wall 17 to be driven bymotor 38. Roller drum 36 is securely mounted onto shaft 39, shaft 39being journaled in suitable brackets which are cantilevered outwardlyfrom end wall 14 [the brackets not being shown].

In order to preheat yarn 24 to insure that it is properly lain onconveyor belt 32, tubes 40 and 41 are positioned parallel to each otherin cavity 12 and directly beneath feed rollers 25 and 26. Tubes 40 and41 are respectively connected to supply pipe 42 and 43 which also serveto support tubes 40 and 41 in cavity 12. Tubes 40 and 41 are providedwith openings 45 which direct the incoming heated air downwardly towardconveyor belt 32 in a converging manner so that yarn 24 which passesbetween tubes 40 and 41 is preheated and properly deposited ontoconveyor belt 32.

"Electrical resistant heater elements 46 are supported in cavity 12 bymeans of brackets 47 and 48 which are secured to side walls 17 and 18 byany convenient means. Heating elements 46 are provided with fins 50which direct the air by heating elements 46 and upwardly toward conveyorbelt 32. Fans 52, 53 and 54 are respectively mounted on the ends ofshafts 55, 56 and 57 adjacent side wall 18, shafts 55, 56 and 57 beingjournaled for rotation in side walls 17 and 18. Shafts 55, 56 and 57also receive fans on their ends adjacent to side wall 17, however, onlyone of them is shown and it has been given the reference numeral 59[fans adjacent side wall 17 hereinafter being referred to as fans 59].Shafts 55, 56 and 57 extend through side wall 17, are interconnected bya pulley mechanism which is of the conventional type and is driven bymotor 61. The fans as herein shown are adapted to blow the air away fromtheir adjacent side wall toward the center of cavity 12 so that the aircomes into contact with resistant heating elements 46 and is directedupwardly through conveyor belt 32 by fins 50 to engage yarn 24.

After yarn 24 exits chamber 11, it immediately begins to cool uponcontacting the ambient air surrounding chamber 11 and is further cooledby means of forced air which exits pipe 62 through openings 63 therein.Pipe 62 is supported by any conventional means [not shown] and receivesair from a suitable source [not shown].

After yarn 24 has been cooled below 185 F. it is removed from conveyorbelt 32 for further cooling. Takeup rollers 70 and 71 are respectivelymounted on shafts 72 and 73 which in turn are journaled in supportbrackets 75 and 76 and support brackets 77 and 78, respectively. Takeuprollers 70 and 71 and parallel to each other and to conveyor drum 36 andreceive an open meshed conveyor belt 80. Shaft 72 is connected to shaft39 by a sprocket and chain arrangement 81 and is adapted to providetakeup roller 70 with a peripheral speed which is equal to theperipheral speed of conveyor drum 36 so that the rate of speed ofconveyor belts 80 and 32 are equal.

Pinion rollers 82 and 83 are respectively mounted on shafts 84 and 85and are parallel to and are spaced vertically above takeup rollers 70and 71, respectively. Pinion rollers 82 and 83 are in frictional contactwith belt so that movement of belt 80 produces a rotation in pinionrollers 82 and 83. Shafts 84 and are respectively journaled in slot 86of support bracket 75 and a like slot in support bracket 76 which is notshown and in slot 87 of support bracket 77 and in a like slot in support78 which is not shown. Shafts 84 and 85 in effect float in theirrespective slots to compensate for the differential thicknesses of yarn24 and belt 80. Motor 90 which is mounted on an L-shaped bracket 91which in turn is secured to base plate 10 drives fan 92 to cause air tomove upwardly through the conveyor belt 80 and contact yarn 24 so as tofurther cool the same. Pinion roller 82 cooperates with belt 80 to feedyarn 24 onto belt 80 and pinion roller 83 cooperates with belt 80 toprovide a tensioning means for the yarn take-up. Yarn 24 may be taken upby any convenient means such as by bobbin 95.

The product obtained from this apparatus and the following method is afully bulked continuous filament acrylic yarn having not less than 40%bulk, a tenacity of not less than 1.6 -g.p.d. and at least 30%elongation in the bulked form. Bulking by the best of the previouslycited prior art processes produces a yarn having a bulk of 27%, atenacity of 1.9 g.p.d. and elongation of less than 18%.

The method of this invention is concerned with the full bulk developmentof textured yarn 24 which is obtained from any suitable yarn source.Yarn 24 is fed vertically downwardly at a constant rate of speed bymeans of feed rollers 25 and 26 into cavity 12 which may be called thebulk development zone. In cavity 12, yarn 24 is received by the uppersurface of conveyor 32 which conveys yarn 24 across heater elements 46which define a heat zone at a speed which is significantly slower thanthe rate of yarn infeed so that yarn 24 may realize its full shrinkageand bulk development while being suspended in a substantiallyfrictionless and tensionless state. Yarn 24 is maintained in atensionless state by fans 52, 53, 54 and 59 which blow air acrossheating elements 46 and upwardly through conveyor belt 32. Thetemperature of the upwardly moving air is greater than the second ordertransition temperature of the yarn which is approximately 210 F. in dryheat. With yarn 24 suspended above the surface of conveyor belt 32, itis heated to a temperature being greater than its second ordertransition temperature and full bulk is developed in the yarn due to theabsence of any tension or frictional forces which normally act on theyarn. The yarn must not be in contact with any surface for even its ownweight and the friction resulting therefrom while in contact with thesurface is enough to prevent the full bulk development of the yarn.

The bulked yarn departs chamber 12 and resultingly the bulkingenvironment through slot 33 whereupon it is immediately subjected toambient conditions surrounding the apparatus for immediate cooling toabout 177 F. before leaving the surface of belt 32. Yarn 24 is thenforwarded to yarn cooling conveyor belt 80 where fan 92 forces airupwardly through conveyor belt 80 to further cool yarn 24 to atemperature of below approximately F. The full bulked yarn is then fedbetween belt 80 and roller 83 whereupon it is subjected to a tensionforce by means of take-up bobbin 95.

Multifilament yarns of a large range of denier and varying degrees oftwist may be processed by this apparatus and method so long as the yarncan be applied to the belt in a manner which is completely free fromtension.

Example Acrylic fibers which were comprised of a copolymer of 97%acrylonitrile and 3% vinyl acetate were texturized by means of a falsetwist process and were fed into cavity 12 by means of feed rolls 25 and26 at a rate of 80 f.p.m.

The yarn which is comprised of a plurality of acrylic fibers was laidonto conveyor belt 82 which was traveling at a rate of 25 f.p.m. Thedifferential speed between feed (80 f.p.m.) and belt (25 f.p.m.) allowedfor contraction during bulk development. The belt speed provided aresidence time of four seconds in chamber 11. The yarn was subjected toa bulking temperature of 368 F. while in the heat zone and while beingsuspended above the surface of conveyor belt 32. The yarn was thenquenched to a temperature of below 176 F. after exiting chamber 11 whileremaining on conveyor belt 32. The resulting yarn had the physicalproperties of 1.9 grams per denier, 34 percent elongation in the bulkedform and developed bulk of 40%.

What is claimed is:

1. A method for fully developing the bulk in textured yarn comprisingthe steps of:

(a) drawing continuous multifilament textured yarn from a source ofsupply at a first selected rate;

(b) feeding said yarn at said first selected rate of speed into asubstantially enclosed chamber and onto an open-meshed, endless conveyorbelt means, said conveyor belt means traveling at a second selected rateof speed being slower than said first selected rate of speed;

(c) transporting said yarn through a heat zone located in said chamberby said conveyor belt means to raise the temperature of said yarn abovethe range of 185-225 F. and to fully bulk said yarn;

(d) directing a continuous blast of a heated gas upwardly through saidconveyor belt means and against said yarn while in said heat zone tolift said yarn upwardly and to support said yarn in a substantiallytensionless and frictionless state above said conveyor belt means duringfull bulking;

(e) moving said yarn out of said heat zone and out of said chamber bysaid conveyor belt means; and

(f) cooling said yarn to a temperature being below 185 F. before saidyarn is subjected to external forces.

2. The method of claim 1 wherein the filaments of said multifilamentyarn are comprised of an acrylom'trile copolymer.

3. The method of claim 2 wherein the heated gas is heated air.

4. The method of claim 3 wherein the first selected rate of speed is atleast twice that of the second selected rate of speed.

5. The method of claim 4 wherein said yarn is cooled to a temperaturebelow 185 F. before being removed from said conveyor belt means.

6. The method of claim 5 wherein said yarn after being removed from saidconveyor belt means is further cooled to a temperature being less than120 F. prior to packaging.

7. An apparatus for fully developing the bulk in a continuousmultifilament textured yarn comprising:

(a) a substantially enclosed chamber;

(b) open-meshed moving conveyor belt means partially residing in saidchamber;

(c) a heat zone located in said chamber through which passes saidconveyor belt means;

(d) yarn feeder means for drawing said yarn from a source and fordepositing said yarn on said conveyor belt means prior to said conveyorbelt means entering said heat zone; and

(e) air blower means for introducing air to said heatzone where said airis heated and for forcing said heated air through the portion of saidconveyor belt means residing in said heat zone at a velocity sufficientto lift said yarn from said belt and to suspend said yarn above saidbelt in a substantially tensionless and frictionless state while in saidheat zone, said heated air raising the temperature of said yarn to above-225 F. to allow full bulk to develop while being suspended in saidtensionless and frictionless state.

8. An apparatus for fully developing the bulk in continuousmultifilament textured yarn comprising:

(a) a chamber defining a cavity and having a yarn inlet, a conveyor exitslot and a conveyor inlet slot;

(b) means located adjacent said yarn inlet for draw- .ing said yarn froma source and for feeding said yarn into said chamber through said yarninlet at a first selected rate of speed;

(c) first and second conveyor rollers respectively mounted for rotationin said chamber cavity and externally of said chamber;

((1) anopen-meshed conveyor belt being mounted on said defining a patharound said first and second conveyor rollers, said path extendingthrough said conveyor exit and inlet slots and beneath said yarn inletin said cavity to reveive said incoming yarn;

(e) means for driving a selected one of said rollers and resulting saidconveyor belt at a second selected rate of speed being less than saidfirst'selected rate of speed;

(f) heating elements positioned in said cavity and beneath a length ofsaid conveyor belt to define a heat zone encompassing said length ofsaid conveyor belt; and

(g) blower means for directing air against said heating elements andupwardly through said conveyor belt to lift and suspend said yarn in asubstantially tensionless and frictionless state above said conveyorbelt and to raise the temperature of said yarn to above the range185-225 F. while in said suspended state.

9. The apparatus of claim 8 wherein a second blower means is mountedexternally of said chamber and adjacent said second conveyor roller,said second blower means adapted to direct sufiicient quantities ofcooling air onto yarn to lower the temperature thereof to below 185 F.before said yarn is removed from said conveyor belt.

10. The apparatus of claim 9 wherein a pair of spacedapart and paralleltakeup rollers are horizontally positioned so that a selected one ofsaid takeup rollers is located adjacent to and in communication withsaid second conveyor roller, means for driving said takeup roller, atakeup open meshed conveyor belt mounted for movement on said takeuprollers and a pair of parallel pinion rollers positioned verticallyabove respective ones of said takeup rollers and in frictional contactwith said takeup belt whereby a movement of said takeup belt produces arotation in said pinion rollers, said pinion rollers and said takeupbelt cooperating to pull said yarn from said conveyor belt means and toprovide a tensioning means for yarn packaging.

11. The apparatus of claim 10 wherein a fan is positioned beneath saidtakeup belt between said takeup rollers, said fan adapted to direct airupwardly through said takeup belt to contact and further cool said yarn.

References Cited UNITED STATES PATENTS 2,974,391 3/1961 Speakman et al.3,235,935 2/1966 Daruwalla 28-72.2 3,241,212 3/1966 Evans et al.3,268,971 8/ 1966 Lockwood.

LOUIS K. RIMRODT, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,457,602 July 29, 1969 John C. Oatfield et a1.

It is certified that error appears in the above identified patent andthat said Letters Patent are hereby corrected as shown below:

Column 2, line 66, "1" should read l2 Column 6, line 18, "said" shouldread and line 39, after "onto" insert said Signed and sealed this 14thday of April 1970.

(SEAL) Attest:

Edward M. Fletcher, Jr. E.

Attesting Officer Commissioner of Patents

